problem subsonic app

[milhouse]

hello,

i have a problem to connect my server subsonic whith the subsonic apps, the server connexion test is ok , but when i go to the librairie i've this message:

attempt to invoke virtual method 'java.util.list net.sourceforge.subsonic.android app.domain.indexes.getArtist() on a null object reference,

my server work fine

anybody have an idea? thank you

my config: raspberry PI Jessi lite subsonic 6.1.1 oracle-java8-jdk

smartphone android 6.0.1 nexus 5